I went on a pack trip into Hellroaring Creek in Montana from the 4th - 8th of August. Hellroaring Creek is remote (16 miles in by horse). You access it from Box Canyon which is south of Big Timber, Montana. The actual camp site is only 8 miles north of the Yellowstone Park boundary. It was cutthroat heaven given that it was easy to catch over 50 fish in a day!!